Root-Derived Trans-Zeatin-Type Cytokinins Increase Cold Tolerance in Rice Seedlings by Regulating Energy Metabolism

Area of Science:

• Plant Physiology
• Molecular Biology
• Agricultural Science

Background:

• Rice seedlings are vulnerable to cold stress, impacting crop yield.
• Cytokinins are vital plant signaling molecules involved in stress responses.
• The precise role of cytokinins in rice cold stress adaptation is not fully understood.

Purpose of the Study:

• To investigate the mechanism of cytokinin-mediated cold stress response in rice.
• To elucidate the role of trans-zeatin (tZ)-type cytokinins in rice chilling adaptation.
• To identify potential pathways for enhancing rice cold resistance.

Main Methods:

• Comparative transcriptomic and metabolomic profiling of cold-tolerant and cold-sensitive rice cultivars under low temperature.
• Analysis of cytokinin-defective mutants (e.g., abcg18) to assess cytokinin transport.
• Exogenous application of trans-zeatin (tZ) to evaluate its effect on cold tolerance and energy metabolism.

Main Results:

• Cold-tolerant rice exhibited higher levels of root-derived tZ-type cytokinins in leaves, increased energy metabolism, and elevated ATP content.
• A tZ transport-deficient mutant showed reduced cold tolerance and impaired energy metabolism.
• Exogenous tZ application improved energy metabolism and cold tolerance in sensitive rice and mutants.

Conclusions:

• Root-derived tZ-type cytokinins enhance low-temperature adaptation in rice seedlings by promoting energy metabolism and maintaining cellular energy homeostasis.
• The transport of tZ-type cytokinins is crucial for rice cold stress response.
• Manipulating cytokinin signaling pathways offers a promising strategy for improving rice cold resistance.